Development of postoperative tissue adhesions is a common concern and a consequence of a pathophysiological process of healing following a surgery. Postoperative adhesions and scar formations are a major cause of serious complications including peritoneal adhesions, tendon adhesions, soft tissue adhesions after orbital injury and peripheral nerve adhesions, hence hindering a healthy recovery of a human body. Formations of adhesions are remarkable post operations of cardiac surgery, gynecological surgery and orthopedic surgery. Common methods of preventing adhesion formations are medical treatments to inhibit fibroblastic proliferations, biological therapies, better surgical techniques, and barriers placed in between tissues.
The chitosan (CS) is a natural alkaline polysaccharide and is produced by deacetylation of chitin. Chitosan has found many biomedical uses with distinct benefits of being biocompatible, biodegradable, antibacterial and hemostatic, as well as capability of boosting tissue regeneration and strong cellular adherence. Considerable amounts of studies of chitosan in recent years have shown characteristics of chitosan in preventing postoperative adhesions and reducing fibroblastic growth on damaged tissues either in a form of film or gel.
Complex polyelectrolyte films have emerged as important components of new membrane materials with wide applications such as in phase separation, nanofiltration, fruit preservation, and biomedicine. However, pure chitosan films formed as a type of polyelectrolytes are subject to poor mechanical toughness, fast dissolution and quick degradation while embedded in body fluids. As such, applications of pure chitosan films are restricted to a certain aspect.
The present disclosure describes a method of preparing chitosan complex films to improve properties of chitosan complex films in mechanical toughness and extending the time chitosan complex films take to degrade. Polyvinyl alcohol (PVA) has good biocompatibility, being water soluble, and is a commonly used biomedical material as a protective coating on wounds and an embolization agent in drug delivery. In addition, PVA has good film-forming ability and is compatible with CS, especially having superior mechanical properties as the most remarkable benefits. There are two common methods of preparing complex films of PVA and chitosan, physical blending and chemical crosslinking. A homogeneous solution results after physical blending of PVA and chitosan due to formations of hydrogen bonds between the two polymeric molecules of PVA and chitosan. Chitosan complex films formed from the blended homogeneous solution are easy to swell and prone to fast dissolution in body fluids, resulting in rapid loss of films and less resistive barriers for anti-adhesion purposes. Chitosan complex films prepared by the chemical crosslinking method may have superior performance in applications as medical materials, but often contain harmful chemicals to human as most of the crosslinking agents such as glutaraldehyde are toxic.